Wrapped pulp bale, method for wrapping a pulp bale and punching device for carrying out the method

ABSTRACT

The invention relates to a wrapped pulp bale of the kind which, apart from a proper bale, comprises an enveloping wrapping which is folded along opposite faces of the bale while forming mutually overlapping parts in which the paper lies in two or more layers on top of each other. For holding the wrapping against the proper bale, sets of lugs (26) are provided in the overlapping parts of the wrapping, each set of lugs including a number of lugs corresponding to the number of paper layers, which are punched out from the paper layers while leaving through holes therein, and folded along a common folding line (25) as well as jointly inserted between the inside of the innermost layer of paper and the outside of the bale in order to be held therebetween.

TECHNICAL FIELD OF THE INVENTION

In a first aspect this invention relates to a wrapped pulp bale of thekind which, apart from a proper bale, comprises a wrapping or cover ofpaper which envelopes the same and which is folded along opposite facesof the bale while forming overlapping parts in which the paper lies intwo or more layers on top of each other, the wrapping being providedwith means to keep the same against the bale.

PRIOR ART

A usual method for ensuring the keeping of paper covers on pulp bales isto put at least one single steel wire around the individual bale and thecover arranged outside the same, more precisely in such a way that thewire surrounds and braces the very parts of the paper which are foldedtowards opposite faces of the bale and overlap each other, so that theseparts cannot be removed from the faces of the bale. This method is,however, in practice expensive and complicates the process oftransporting the bales from the pulp mill to the paper mill,particularly the shredder thereof. Thus, the actual consumption of steelwire causes an inevitable and for every bale repeatedly occurringmaterial cost falling upon the pulp producer. Furthermore, when thebales arrive to the paper mill, the wire has to be removed from thebales before these can be fed into the shredder in question. This callsfor a special, mechanical wire-cutting equipment, as well as aparticular post-handling of the wire scrap which is left after cutting.

With the purpose of getting away from the use of steel wire, which isprice rising in many respects, attempts have been made to keep the papercover on pulp bales by means of adhesives. Thus, WO91/10594 discloses apacking machine which, in addition to the necessary paper-foldingcomponents, comprises a number of adhesive sprayers by means of whichthe overlapping parts of the paper cover can be internally sprayed withadhesives, which after a certain time of binding (during which specialclamp devices hold the overlapping parts pressed to the bale) gives aholding adhesive joint which is able to replace the steel wires. Aserious disadvantage of this method is, however, that adhesivesrepresent an extraneous component when the wrapped pulp bales are lateron received in the paper mill and in their entirety, that is includingthe paper cover, defibrated to be taken out in form of a beater to thepaper making machine. The paper maker is therefore moderately inclinedto directly use such wrapped pulp bales with adhesive-mixed papercovers. The alternative is to remove the paper covers before tearing thebale, but this would in turn imply a bad utilization of the raw materialof fibre available in the paper cover itself. In addition, the adhesiveis an article of consumption which in itself entails a non-negligiblematerial cost. Another disadvantage is the fact that adhesives require aconsiderable time to set; something which may create a bottleneck in thepackaging line of the pulp mill.

OBJECTS AND FEATURES OF THE INVENTION

The present invention aims at removing the above-mentioned disadvantagesof the previously known technique and at creating a wrapped pulp balewhich without detriment can be directly used in the paper mill. Thus, aprimary object of the invention in a first aspect is to create a wrappedpulp bale the paper cover of which is kept reliably in place withoutsuch additional means as adhesives or steel wires. More precisely, thepaper cover should be held by using holding means of a mechanical natureincluded in the cover itself, which means can be produced in an easy andeffective way and which do not require any handling at all in the papermill.

According to the invention, at least the primary object thereof isattained by the features defined in the characterizing clause of claim1.

In a second aspect, the invention also aims at achieving a bale wrappingmethod by means of which wrapped pulp bales can be produced in a quick,effective and inexpensive way. The features of this method are definedin claim 4.

In a third aspect, the invention also relates to a punching device forcarrying out the method according to the invention. The features of thispunching device are defined in claim 5. Preferred embodiments of thepunching device according to the invention are furthermore defined inclaims 6 to 8.

FURTHER ELUCIDATION OF THE PRIOR ART

In SE 331 025 (U.S. Pat. No. 3,430,413) an envelope of paper intendedfor the wrapping of bottles is described which is kept in place aroundthe contents by means of foldable lugs which are brought into engagementwith each other by means of a special machine. In this case, however,each lug is punched individually before they are interengaged.Furthermore, NO 50 171 discloses a method in which holes are punched intwo layers, e.g. of paper, lying on top of each other for the purpose ofkeeping the layers together. In this case, however, the actual lockingtakes place by means of adhesive-like materials, such as wax, gum,varnish or the like.

BRIEF DESCRIPTION OF THE APPENDED DRAWINGS

In the drawings:

FIG. 1 is a schematic perspective view illustrating a wrapping stationin which a number of punching devices according to the present inventionare included and in which a pulp bale wrapped according to the inventionis illustrated,

FIG. 2 is a front view of a carrier equipped with several individualpunching devices, shown behind a bale outlined with dash dotted lines,

FIGS. 3 and 4 are longitudinal sections through a punching deviceaccording to the invention, shown in two different positions offunction,

FIG. 5 is a vertical view illustrating how several punching devicesseparated level-wise may be part of one of two carriers, included in thestation according to FIG. 1,

FIG. 6 is an enlarged perspective view showing a punching tool includedin the punching device according to the invention, and

FIGS. 7 to 13 are simplified side views illustrating a number ofdifferent steps during the punching of a separate set of lugs accordingto the invention.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

In FIG. 1 a wrapping station is designated 1 in which two carriers 1',1" are included which comprise a plurality of schematically shownpunching devices 2 according to the invention. The carriers 1', 1" havethe character of jaws which can be moved linearly to and fro each other,e.g. by means of hydraulic cylinders 3. 4 generally designates aconveying equipment on top of which an arriving pulp bale 5 withadherent paper cover is shown as well as a ready-wrapped bale 5'. As isclearly illustrated in connection with the arriving pulp unit 5, thisconsists on one hand of a proper bale 6 and on the other hand a wrappingor cover 7 of paper. In a preceding station included in the samepackaging line as station 1, the paper cover 7 has been wrapped aroundthe bale 6 as well as folded along opposite faces of the bale whileforming parts 8, 8' overlapping each other. More precisely, the lowerpart 8 has been folded towards the bale in a first step, whereupon theupper part 8' has been folded towards the part 8 in a second step. Inother words, the part 8' is applied to the outside of the part 8. Itshould be evident, that the paper web constituting the cover 7 lies inseveral layers on top of each other in the folded parts 8, 8' whichpartly overlap each other.

The bale itself 6 usually has the form of a pressed, homogeneouslycontinuous body of fibres. This fibre body is in the mainparallelepipedical, e.g. having the size of 80×60×50 cm and a weight ofabout 200 kg. In some cases, the bale 6 or the contents of the cover 7may consist of a plurality of relatively stiff sheets of fibre placed oneach other, together forming a parallelepipedical body or bundle.

Reference is now made to FIGS. 3 to 6, which in detail illustrate apreferred embodiment of a punching device according to the invention. Asmay be most clearly seen in FIGS. 3, 4 and 6, each individual punchingdevice 2 comprises a front jaw 9 in which there is an opening 10 inconnection to which a protruding, edge-equipped cutting or punching tool11 is arranged the purpose of which is to punch out sets of lugs in theoverlapping parts 8, 8' of the paper cover 7 in a way which is closerdescribed below in association with FIGS. 7 to 13. In the example shown(see FIG. 6), the opening 10 has essentially a rectangular orquadrangular form, while the punching tool 11 is mainly U-shaped andsurrounds the opening 10. More precisely, this U-tool is turned to openupwards, in that the same comprises a lower first edge 12 from theopposite ends of which two vertical, mutually parallel edges 13, 13'extend. It should be evident, that when these edges cut through thepaper in the cover 7, a set of lugs is created comprising a number ofindividual vertically down-hanging lugs corresponding to the number ofpaper layers.

Inside or behind the jaw 9 a dog or driver 14 is arranged, which iscapable of swinging around a first hinge 15. The dog is in the form ofan essentially J-shaped body having an arched finger 16 which isdistanced from the hinge 15 so that the free end 16' of the finger (seeFIG. 10) can move in an arch-shaped path. In the preferred embodiment,the jaw 9 forms a gable to a house, in its entirety designated 17, whichis movably arranged in relation to the carriers 1' and 1" respectively(whose front wall is designated 18 in FIGS. 3 to 5). More precisely, thedog 14 is located in a frontal case-shaped portion 17' of the house 17.This case-shaped portion 17' of the house opens to the rear in abox-shaped portion 17" of the house. In said box-shaped portion, thereis a suitably pneumatically driven piston-cylinder mechanism 19, thepiston rod of which is connected to the dog 14 via a second hinge 20. Athird hinge 21 connects the cylinder of the mechanism to the box-shapedportion 17" of the house. The house 17 is, in its entirety,spring-loaded by means of a spring 22, e.g. a screw compression spring,which always aims at moving the house to the position shown in FIG. 3where the jaw 9 is at the maximum distance from the front wall of thecarrier 18. In this position, a nut 23 on a dowel 24 of the box portion17" serves as an adjustable stop for the house, more precisely byabutting against an inner wall 18' within the carrier 1' and 1". Itshould be particularly pointed out that the spring 22 in practice shouldbe rather powerful, implying that the house 17 and the jaw 9 can bepressed into the carrier only by a relatively great force.

As may be seen in FIGS. 1, 2 and 5, each carrier 1', 1" comprises aplurality of punching devices divided in sets of rows 2. More precisely,the devices are placed in three rows separated level-wise with, in thiscase, seven devices in each row. Owing to the fact that each punchingtool is individually movable in relation to the carrier in common, byseparately being part of a movable, spring-loaded house of the kinddescribed above, it is secured that the punching tools can reliably cutinto the paper cover even if the lateral surface of the bale in questionshould be uneven.

Reference is now made to 7 to 13 which in detail, though schematically,illustrate the different working steps during the punching of therequired sets of lugs in the paper cover. In FIG. 7 a part of the properpulp bale or the body of pulp fibre 6 is shown, while the paper cover ingeneral is designated 7. In FIG. 7 the cover is shown comprising anumber of layers of papers designated 7' lying on top of each other.These multiple layers of paper exist in different numbers in the area ofthe two overlapping parts 8, 8' along the lateral surfaces of the bale.When the U-shaped punching tool 11 is pressed against the layers ofpaper in the direction of the arrow in FIG. 7, the edges of the tool 12,13, 13' will cut through all layers of paper as illustrated in FIG. 8.In this connection, individual U-shaped lugs are provided in each layerof paper, each lug hanging down vertically from horizontal folding lineswhich are designated 25 in FIG. 8. When the punching tool has reachedits bottomed position in which the jaw 9 lies tight against the lateralsurface of the pulp bale, the driver 14 is activated, more precisely insuch a way that the same, by means of the cylinder 19, is turned in thedirection of the arrow in FIG. 8. In doing so, the front portion 16' ofthe finger 16 (which is designed with an angular notch) will seize thefree ends of the lugs 26. On continued turning of the driver, the freeend 16' of the finger will move in an arch-shaped path around the hinge15 and firstly pass through the opening 10 and then moveoutwardly/upwardly through the same. At last the driver will reach anupper end position, shown in full lines in FIG. 12. The driver has thenintroduced the set of paper lugs 26 in a folded-up state in theinterface between the inner side of the paper cover and the outsidesurface of the proper pulp bale 6. When the driver is thereafter turnedback to the position shown in FIG. 12 with dashed lines, the set of lugs26 remains in its folded-up position where it is kept by means of atleast a light squeezing action between the outer cover and the innerpulp bale. Finally, the punching device 11 is removed from the bale asillustrated in FIG. 13.

When both the carriers 1', 1" have been removed from the pulp bale 5'positioned in the wrapping station 1 according to FIG. 1, the papercover 7 thereof will be reliably kept against the very body of the baleby means of a plurality of individual sets of lugs 26 in connection toeach one of the holes 27 which have been punched in the cover.

Conceivable Modifications of the Invention

The invention is not limited solely to the embodiment described aboveand shown in the drawings. Thus, it is conceivable to use a few, e.g.only one, punching tools for locking the cover to the bale. In caseseveral tools occur on each carrier, it is further conceivable toarrange the tool in a fixed position in relation to the carrier insteadof the individually movable, spring-loaded arrangement as has beenexemplified in the drawings. Further, it is conceivable to punch lugswith another shape than the rectangular one exemplified in the drawings.For example, the lugs and the through holes may have a triangular form,the individual punching tool consisting of only two edges arranged in aV-shape. Also, the required driver or dog for introducing the set oflugs behind the paper cover may be realized in another way than the onedescribed above.

We claim:
 1. A method for wrapping a pulp bale with a wrapping or cover(7) of paper, said wrapping or cover put around the bale and foldedalong opposite faces thereof while forming mutually overlapping parts(8, 8') in which the paper lies in a plurality of layers on top of eachother, said wrapping being provided with holding means for holdingagainst the bale, wherein one or more sets of lugs (26) are provided inthe overlapping parts (8, 8') of the wrapping, each of said sets of lugsbeing made by jointly punching, from the paper layers lying on top ofeach other, a number of individual lugs corresponding to the number oflayers, said lugs being folded along a common folding line (26) andjointly inserted between the inside of the innermost paper layer and theoutside of the bale so as to be held therebetween.
 2. A wrapped pulpbale comprising a wrapping (7) of paper enveloping said bale, whichwrapping is folded along opposite faces of said bale while formingmutually overlapping parts (8, 8') in which the paper lies in two ormore layers on top of each other, the wrapping being equipped withholding means to hold the same against the bale, wherein said holdingmeans comprises sets of lugs (26) provided in said overlapping parts (8,8') of said wrapping (7), each set of said sets comprising a number oflugs corresponding to the number of layers of paper (7'), said lugsbeing punched out from paper layers while leaving through holes (27)therein, and folded along a common folding line (25) as well ascollectively inserted between the inside of the inner paper layer andthe outside of the bale in order to be held therebetween.
 3. The wrappedpulp bale according to claim 2, wherein said folding line (25) islocated to the area of an upper part of the through hole (27) in thepaper layers, the folded-in set of lugs (26) extending upwardly fromsaid hole.
 4. The wrapped pulp bale according to claim 2, wherein two ormore sets of lugs separated level-wise are punched in the overlappingparts (8, 8') of the wrapping (7), with sets of lugs in each row.
 5. Thewrapped pulp bale according to claim 3, wherein two or more sets of lugsseparated level-wise are punched in the overlapping parts (8, 8') of thewrapping (7), with sets of lugs in each row.
 6. A punching device forpreparation of a wrapped pulp bale, said bale being wrapped with awrapping or cover of paper, said wrapping or cover being put around thebale and folded along opposite faces thereof while forming mutuallyoverlapping parts in which the paper lies in a plurality of layers ontop of each other, said wrapping being provided with holding means forholding against the bale, wherein one or more sets of lugs are providedin the overlapping parts of the wrapping; said punching devicecomprising a jaw which may be pressed against the bale and in which thethere is at least one opening in association with which a protruding,edge-equipped cutting or punching tool is arranged, whose purpose is tojointly punch out sets of lugs in several layers of paper, and that adriver is moveable to and fro through said opening so as to fold andinsert the punched set of lugs between the inside of the inner mostpaper layer and the outside of the bale itself, whereby a number ofindividual lugs corresponding to the number layers is jointly punchedfrom the paper layers.
 7. A punching device according to claim 6,wherein said driver is a body (14) which is placed behind the jaw (9)and may be swung around a hinge (15), said body having an arched finger(16) which is distanced from said hinge (15) to be able to move in anarch-shaped path with its free end (16').
 8. A punching device accordingto claim 6, wherein said jaw (9) carrying the punching tool (11)constitutes a gable of a house (17) within which the driver body (14) islocated, and that said house is movably arranged in relation to acarrier (1', 1") being common to several corresponding houses andactuated by a spring (22), which always aims at distancing the house andthe punching tool (11) thereof from the carrier towards an external endposition, and against the action of which the house and the punchingtool are compressible in the direction towards the carrier.
 9. Apunching device according to claim 7, wherein said jaw (9) carrying thepunching tool (11) constitutes a gable of a house (17) within which thedriver body (14) is located, and that said house is movably arranged inrelation to a carrier (1', 1") being common to several correspondinghouses and actuated by a spring (22), which always aims at distancingthe house and the punching tool (11) thereof from the carrier towards anexternal end position, and against the action of which the house and thepunching tool are compressible in the direction towards the carrier. 10.A punching device according to claim 8, wherein said carrier (1', 1")comprises two or more sets or rows of tools separated level-wise, withseveral tools in each row.